Apparatus for refrigeration



Nov. l5, 1938. Bo F. RANDEL 2,136,395

4 APPARATUS FOR REFRIGERATION- Filed March 9, 1956 4 Sheets-Sheet 2 BYBQFOLK?. RANVEL.

ATTORNEY Bo- F. RANDEL' APPARATUS FOR REFRIGERATION Filed March 9, 193e4 sheets-sheet s hihi' l' l INVENTOR o FOLKE RAN DEL ATTORNEY Nov. 15,1938.

BO F. RANDEL APPARATUS FOR REFRIGERATION Filed March 9, 195e4.Sheets-Sheet 4 Y INVNTOR C. FoLKE HANDEL (2.r *L9-M4144 ATTORNEYPatented Nov. 15, 1938 APPARATUS FOR REFRIGERATION Bo Folke Randel, SanDiego, Calif.

Application March 9,

3 Claims.

1936, serial No. 67,867

(Granted under the act of `March 3, 1883, as amended April 30, 1.928;370 O. G. 757) This invention relates to refrigeration and it has as aphysical basis the fact that the vapor pressure of a solvent in a saltsolution is lower than the vapor pressure of the pure solvent. For

example, the vapor pressure of a solution of calcium chloride in wateris lower than the vapor pressure of pure water.

The principal object of the present invention is the provision of amethod of and apparatus l0 for employing this physical law forthepurpose of reducing the temperature of a refrigerating medium forcirculation through a cooling system. In its essentials the inventioncomprises two intercommunicating vessels, one an evaporator forcontaining a pure solvent and the other an absorber containing asolution of a salt in the solvent. Both vessels are preferably evacuatedof air. Under thesel conditions the vapor pressure in the evaporator,being greater than that in the absorber, the vaporized solvent will flowfrom the former to the latter and will be absorbed by the solutiontherein. The evaporation of the solvent in the evaporator will beaccompanied by the absorption of a certain amount of heat from thesurrounding environment, such as a fluid employed for refrigerating orcooling purposes, and the absorption of the vapor in the absorber willbe accompanied by the liberation of an equal amount of heat. If thisevaporation and absorption should continue, the pure solvent in theevaporator would diminish in volume and also an excess quantity ofsolvent would accumulate in the absorber and dilute the solutiontherein.This tendency, however, is avoided by withdrawing some of the solutionfrom the absorber and passing it to aA generator where an amount o1' thepure solvent equal to vthat absorbed in the absorber is vaporized. Thisvaporized solvent is then condensed and returned to the evaporator randacertain amount of the vconcentrate solution 'is returned. to theabsorber, thusgmaintaining the volumes of the solvents in both `of thesevessels substantially constant. yThe solvent and solution v'returned tothe evaporator andv ab- 45 sorber areA preferably sprayed thereinto soas to accelerate the rate of evaporation and absorption in thesevessels. While manyfmediums 'can be employed for the purposes described,a solution oi' pure water and calcium chloride -is used as anillustration in explaining the apparatus. y

With these and other objects in4 view, as well as other advantages thatmay be incident to the use of the improvements, the invention consistsin the parts and combinations thereof hereinafter set" forth andclaimed, 'and with the under- Astanding that the several necessaryelements constituting the same may be varied in proportion andarrangement without departing from the nature and scope of theinvention, as dened in the appended claims.

In order to make the invention more clearly understood, there are shownin the accompanying drawings, means for carrying the invention intopractical use, Without limiting the improvements in their usefulapplication to the particular construction, which, for the purpose ofexplanation, have been made the subject of illustration.

In the accompanying drawings:

Fig. 1 is a diagrammatic view of a refrigerating apparatus embodying.the present invention; and

Figs. 2 to 4 inclusive, are similar views of other forms ofrefrigerating apparatus all embodying and operating in accordance withthe invention.

Referring to the drawings, and particularly to Fig.' 1 thereof, arefrigerating apparatus constructed and lassembled in accordance withthe invention is shown as comprising an evaporator Ill which is partlyfilled with la solvent Il such as pure water, and an absorber I2 whichis partly lled with a solution I3 such as calcium chloride and water.'I'he evaporator I0 and absorber I2 are connected together at theirupper ends by a pipe or conduit I4 and the assembly evacuated of air. Acoil I5 through which a refrlgerating medium is circulated is mountedwithin the evaporator I0 and a coil I6 through which a cooling medium iscirculated is mounted within the absorber I2.

The evaporation of the water in the evaporator Illiand in the absorberI2 creates divflerential vapor pressures in these vessels such as willcause the vaporized water in the evaporator I0 to flowv through the pipeIl and into the absorber I2 where it is absorbed by the solution Il. Theevaporation of the water in the, evaporator III extracts heat from thecoil I5 and the refrigerant. flowing therethrough, which heat isliberated in the absorber I2 and is extracted 'therefrom` through thecooling action of the coll I 8.

By maintaining the temperature of the solution I3 in the absorber atsubstantially 85 F. and the solution' at substantially 50 per cent waterand` 50 per cent calcium rchloride, the vapor pressure in ,this vesselwill correspond tok about '7 mm. of Hg. This will therefore be theyvapor pressure in` the' evaporator I0 and will. correspond tovapproximately 42 F. A medium passing 'through the coil vI5 maytherefore be cooled to the theoretical point of this tempera-v ture,which is sufciently low vfor most air or watercooling purposes. l, l

If this evaporation and absorption were to continue, the water II in theevaporator would become depleted and the solution I3 in the absorber I2would become diluted. In order, therefore, to maintain the volumes ofwater II and solution I3 substantially constant and to prevent thesolution- I3 from becoming diluted, an amount of the solution I3 equalto the amount of concentrated solution being supplied to the absorberplus the water absorbed thereby is withdrawn from the lower portion ofthe absorber I2 through a pipe I1 by means of a pump IB driven by amotor I9, and forced through a pipe 20, a heat exchanger 2l and a pipe22 into the upper portion of a generator 23. The pump I8 alsocommunicates through a pipe 24, controlled by a valve 25, with a nozzle26 located in the upper portion of the absorber I2. This nozzle spraysthe solution downwardly over the cooling coil I6 and accelerates therate of absorption of the water vapor.

The generator 23 also contains a quantity 21 of a solution of calciumchloride and water and is also provided with a coil 28 through which a'heating medium, such as steam, is circulated. This coil heats thesolution 21 in the generator 23 and the water vapor generated therebypasses through a pipe 29 communicating with a receiver tank 30. The pipe29 is inclosed for a portion of its length within a water jacket 3|through which cooling water flows from an inlet pipe 32 to an outletpipe 33. The cooling action 'of the water jacket condenses the watervapor and delivers it to the receiver 30 in a liquid state. From thereceiver 30 the pure water 'passes through a pipe 34 controlled by avalve 35 to a nozzle 36 located in the upper portion of the evaporator I6 from which it is sprayed downwardly over the coil I5, thus not onlyaccelerating the rate of evaporation and the extraction of heat from therefrigerant circulating through the coil I but maintaining the volume ofwater I I in the evaporator I0 substantially constant.

The concentrated solution in the generator 23 is returned to theabsorber I2 through a pipe 31 which communicates with the lower portionof the generator and with the pipe 24, and which is provided with avalve 38. ,The flow of the solution back to the absorber I2 is caused bythe combined eect of the pump I8 forcing the solution which is withdrawnfrom the bottom of the absorber, through the pipe 24, and the differencein the hydrostatic heads of the solution in the absorber and generator.The pipe 31, for a portion of its length, passesthrough the heatexchanger 2I so that the heated solution owing from the generator iscooled by the cold solution flowing from the absorber I2, this lastmentioned solution being preheated by the heated solution flowing yfromthe generator 23.

In Fig. 2 there is illustrated a slightly modified embodiment of theinvention. In this particular construction the water jacket 3| isdispensed with and a cooling coil 39 provided within the receiver 30 forcondensing the water vapor developed in the generator 23. Also, anejector 40 is substituted for the spray nozzle 26 in the absorber I2.'I'his ejector 4I) not only delivers the solution to the absorber inatomized form but also accelerates the ilow of water vapor from theevaporator Ill to the absorber I2.

In Fig. 3 there is shown a, still further modified constructionparticularly adapted for reducing the temperature of the air of an aircooling system. In this construction the evaporator I0 and the absorberI2 are surrounded by jackets 4I and 42 respectively, through which airto be cooled by the evaporator, and cooling air for extracting heat fromthe absorber, are circulated. The cooling of the air ilowing through thejacket 4I is facilivtated by providing a plurality of pipes 43, whichextend horizontally through the absorber from side to side in superposed,spaced relation and through which the refrigerating air passes dui'-ing its ow through the jacket 4I. In a like manner the absorber I2 isprovided with a plurality of transversely extending pipes 44, throughwhich the coolingair flowing through the jacket 42 is adapted to pass,thus increasing the rate at which it extracts heat from the solution I3.The receiver 30 may also be constructed in a similar manner by providinga surrounding jacket 45 and transversely extending pipes 46, throughwhich the cooling air is adapted to pass so as to accelerate the rate ofcondensation of the Water vapor passing to this vessel.

Also, in this construction the lower portion of the absorber I2communicates with the generator 23 through a pipe 41, heating coil 48,and pipe 49, the ow of the solution being aiected by applying heat tothe coil 48 from a suitable source 50. The concentrate solution isreturned to the absorber I2 from the bottom of the generator 23,

through a pipe 52 and a heat exchanger 5I, the latter surrounding aportion of the pipe 41, and a pump 53, which communicates through a pipewith the nozzle 26 in the upper portion of the absorber I2. In otherrespects the operation of the apparatus is similar to that previouslydescribed in connection with Fig. 1.

In Fig. 4 there is illustrated a still further embodiment oftheinvention in which evaporator I0 communicates with the absorber I2through a pipe 54 and a jet compressor including a Venturi tube 55 andspray nozzle 56. The pump I8 withdraws the solution from the lowerportion of the absorber I2 through the pipe I1 and forces it through anejector 51 and pipe 58 to the spray nozzle 56, from which it isprojected through the Venturi tube 55 back into the absorber I2. Aportion of the solution withdrawn from the absorber I2 is forced by thepump I8 into a pipe 59, the end of which projects into the ejector 51and the flow therethrough is controlled by a valve 60. This portion ofthe solution flows through the pipe 59, a heating coil El, where it isheated, and pipe 62 to the generator 23. The pure water vapor developedin the generator then passes through condenser coil 63, where it isliqueed, r

and thence through a pipe'64, controlled by a valve 65, to the spraynozzle 36 in the upper portion of the evaporator I0.

The heated concentrate solution is returned to the absorber through apipe 66, heat exchanger 61 and pipe 68, the end of which projects intothe ejector 51, and thence through the ejector 51 and pipe 58 to thespray nozzle 56. A portion of the pipe 59 extends through the heatexchanger 61 so that the cold solution Withdrawn from the absorber I2 ispreheated prior to passing through the heating coil 6 I, by the heatedsolution passing from the generator b ack to the absorber, thisreturning solution being in turn precooled by the solution passingthrough the pipe 59.

It will be apparent from the foregoing that all of the several modiedconstructionsthereinabove described are basically the same and differonly in vdetails of construction.

Other modifications and changes in proportion l and arrangement of theparts may be made by those skilled in the art without departing from thenature .and scope of the invention, as defined in the appended claims.

, The invention described herein may be manufactured and used by or forthe Government of the UnitedStates of America for governmentalpurposeswithout the payment of any royalties thereon or therefor.

1 claim: u

1. A refrigerating apparatus comprisingJ in combination: an evaporatorcontaining a solvent; an absorber in vapor communication with saidevaporator and containing a solution of a salt and a solvent, theevaporation of the solvent in the evaporatorcausing the absorption ofheat A from the surrounding medium and causing differential vaporpressures in the evaporator and the absorber and a flow of heatedvaporized solvent from the former to the latter, the solvent in saidabsorber being adapted to absorb said vaporized solvent and extract heattherefrom; means within said evaporator through which a refrigeratingmedium is adapted to` be circulated; means in said absorber for coolingsaid solvent; a generator for separating a volume of said solvent fromsaid solution substantially equal to that absorbed thereby' andreturning it to said evaporator; and single means for withdrawing weaksolution from said absorber and delivering the same to said generatorand for also withdrawing concentrated solution from said generator anddelivering the entire amount thereof to said absorber. i

2. A refrigeratingv apparatus comprising in combination: an evaporatorcontaining a solvent; an absorber in vapor communication with saidevaporator and containing a solution of a salt and a solvent,`theevaporationVof the solvent in the evaporator causing the absorption ofheat from the surrounding medium and causing differential vaporpressures in the evaporator and the absorber anda ow of heated vaporizedsolvent from the former to the latter, the solvent in said absorberbeing adapted to absorb said vaporized solvent and extract heattherefrom; means within said evaporator through which a refriga eratingmedium is adapted to be circulated; means in said absorber for coolingsaid solvent; a boiler for vaporlzing a volume of said solvent from saidsolution substantially equal to that absorbed thereby condensing thesame and returning it to said evaporator; and single means forwithdrawing weak solution from said absorber and delivering a portionthereof back to said absorber and another portion thereof to said boilerand for also withdrawing concentrated solution from said boiler anddelivering the entire amount thereof to Asaid absorber commingled withthe Weak solutionldelivered thereto.

3. A refrigerating apparatus comprising in combination: an evaporatorfor containing a solvent; an absorber in vapor communication with saidevaporator and containing a solution of a salt and a solvent, theevaporation of the solvent in the evaporator causing the absorption ofheat from the surrounding medium and causing differential vaporpressures in the evaporator and the absorber and the flow of heatedvaporized solvent from the former to the latter, the solvent in saidabsorber being adapted to absorb said vaporized solvent and extract heattherefrom; means within said evaporator through which a refrigeratingmedium is adapted to be passed; means in said absorber for cooling saidsolvent; a generator; means for conducting a volume of the solution fromsaid absorber to said generator; means for heating the solution in saidgenerator to vaporize the solvent therein; means for condensing saidvaporized solvent and returning it to said evaporator; `and meansincluding an ejector nozzle for returning the concentrate solution fromsaid generator to said absorber, thus to further decrease the vaporpressure in said evaporator and to maintain the volumes of the solventand the solution in said evaporator and said` absorber substantiallyconstant.

BO FOLKE RANDEL. f

